Fig. 1

Surface quantum transport in a Cd₃As₂ thin film. a Low-energy band dispersion of a Dirac semimetal (DSM). DSM consists of two copies of a Weyl semimetal superimposed with opposite chirality ±1. b, c Magnetic orbits mediated by the surface states in a DSM slab with thickness t. The two Fermi-arcs on the top and bottom surfaces are interconnected through the bulk chiral zero mode in b, while the two Fermi-arcs on the same surface deform into a closed Fermi pocket to form a conventional orbit localized at each surface in c. d Out-of-plane transverse (upper panel) and longitudinal (lower panel) magnetoresistances (MRs) of a 100 nm thick Cd₃As₂ film. The right axis of the upper panel shows Hall resistance R_yx. θ indicates an angle between the field B and current I. Filled squares denote the oscillation component observed only in the transverse MR, while open circles denote the 3D bulk oscillations observed in both the transverse and longitudinal MRs. Accompanied by sharp resistance drops in R_xx in the higher field region, R_yx shows plateau-like structures, indicating the appearance of 2D quantum Hall states. e Temperature dependence of the oscillatory components in the transverse and longitudinal MRs and f extracted effective mass m^* plotted as a function of 1/B. The quantum oscillations at higher fields are characterized by larger F_S and m^* than the bulk one, which are ascribed to the surface state